One of the cardinal rules of criminal law is that you NEVER speak to the authorities unless you have a lawyer with you. Anything you say to these detectives about the incident you were involved with, even things you think can't possibly hurt you, can be turned around and used against you at a later point. Your statements/admissions can also give the police probable cause for a search warrant or for your arrest and the filing of charges.
Generally, when the police want you to come in and talk, it's because they don't have enough information to arrest you, but they are hoping to get it from you. Under circumstances like this, you have a Constitutional right to remain silent. Exercising that right can't ever be used against you. But if you choose to talk to the police, every word you say may get you closer and closer to being in trouble.
You just don't know because you're talking to them in a vacuum and don't know what/all they are really looking for. They don't have to tell you and they don't have to be up front with you. It may be that you're not in trouble, but you're certainly of interest to them, which means they likely don't believe what you've told them in the first place, and that doesn't rule trouble out.
Don't call the police back. If they call you tell them that you're waiting to hear from your lawyer and that you don't want to speak to them until you've discussed this with him or her. Then get a lawyer and protect your rights.
There isn't a criminal lawyer worth his or her license to practice law that won't tell you the same thing under these circumstances. You should not talk to the police unless you do so with a lawyer.